The references cited throughout the present application are not admitted to be prior art to the claimed invention.
Anthrax is a bacterial infection produced by Bacillus anthracis. Bacillus anthracis endospores can enter the body through skin abrasions, inhalation, or ingestion. Bacillus anthracis produces an anthrax toxin that is often lethal. (Dixon et al., (1999) N. Engl. J. Med. 341, 815-26.)
Anthrax toxin consists of three proteins, a receptor-binding component designated protective antigen, and two enzymatic components termed edema factor and lethal factor (“LF”). (Mock et al., (2001) Annu. Rev. Microbiol. 55, 647-71.) Lethal factor is a zinc-dependent metalloprotease that appears to exert toxic affects by cleaving mitogen-activated protein kinase kinases (MKKs). (Vitale et al., (1998) Biochem. Biophys. Res. Commun. 248, 706-11, Vitale et al., (2000) Biochem. J. 352 Pt 3, 739-45, Duesbery et al., (1998) Science 280, 734-7, Duesbery et al., International Publication No. WO 99/50439, International Publication Date Oct. 7, 1999.)
Vitale and co-workers have used microsequencing to identify the site in different MKKs that are cleaved by lethal factor. (See Table 1, Vitale et al., (2000) Biochem. J. 352 Pt 3, 739-45.) Lethal factor cleavage of different MKKs occurred within the N-terminal region preceding the kinase domain. Alignment of the sequences flanking the cleavage site revealed some consensus motifs: a hydrophobic residue in position P2 and P1′, and at least one basic residue between P4 and P7. (Vitale et al., (2000) Biochem. J. 352 Pt 3, 739-45.)
Lethal factor has been indicated to cleave synthetic peptides in vitro. (Hammond et al., (1998) Infect. Immun. 66, 2374-8.) In vitro cleavage was inhibited by 1,10-phenanthroline or 10 mM EDTA, both of which chelate zinc.